ABSTRACT Antiretroviral therapy (ART) significantly reduces viral replication and prolongs life, but comorbidities in the ART-sustained HIV population are increasing in prevalence. These include cancer, neurologic disorders, lipid metabolism dysfunction and cardiovascular disease (CVD) that can lead to accelerated aging. HIV-infected individuals, and especially those taking antiretrovirals, exhibit unremitting immune activation and inflammation; conditions that underlie the pathophysiology that contributes to disease development. CVD in the ART-sustained HIV population is higher than the general population (as high as 25%). An important confounding concern is that most ART-sustained persons abuse harmful substances, especially tobacco. The HIV-infected population smokes cigarettes at high rates compared to the general population (up to 70% compared to 17% of the general population) and they smoke heavily. It is well-known that the hazards of smoking lead to major health risks, including CVD (i.e. atherosclerosis, myocardial infarction, stroke). The health toll for tobacco abuse in ART-sustained persons already predisposed to comorbid disease is substantially increased, compared to persons taking antiretroviral agents that do not smoke. Recently, the role of exosomes in viral pathogenesis has been under scrutiny. Exosomes are a unique class of extracellular vesicles (EVs) released by many cell types and are abundantly found in blood and other body fluids. They have multifactorial transcellular functions in health and disease. The role of exosomes is an emerging area of biology that is important for understanding HIV pathogenesis-associated comorbid disease and substance abuse. Our hypothesis is that ART-sustained individuals that smoke tobacco exhibit changes in exosome numbers, proteins and miRNA content that potentiate a proinflammatory and prothrombotic milieu, increasing CVD risk. Our goal in this exploratory R21 is to determine how exosomes impact the underlying inflammation present in ART-sustained persons in the context of tobacco abuse and whether specific changes in exosome cargos can serve as predictive measures of CVD risk or biomarkers of tobacco abuse. In Specific Aim 1, we will determine key pathological changes, and protein and eicosanoid biomarkers of dysfunction elicited by exosomes in ART-sustained individuals that abuse tobacco. Our approach in Specific Aim 2 will be to investigate changes in exosome miRNA composition, and use an integrated biology approach and computational modeling to identify new mechanisms of dysregulation. Understanding the role of exosomes could lead to the design of novel strategies to improve the long term health status in HIV/AIDS persons.